Explanation:
Some 4 billion light-years away, massive galaxy cluster Abell 370
only appears to be dominated by two giant elliptical galaxies
and infested with faint arcs in this sharp
Hubble
Space Telescope snapshot.
The fainter, scattered bluish arcs along with the
dramatic dragon arc
below and left of center are images of galaxies that lie
far beyond Abell 370.
About twice as distant, their otherwise undetected light is
magnified and distorted by the cluster's enormous gravitational mass,
dominated by unseen
dark matter.
Providing a
tantalizing
glimpse of galaxies in the early universe,
the effect is known as gravitational lensing.
A consequence of warped
spacetime it was
first predicted by Einstein a century ago.
Far beyond the spiky foreground Milky Way star at lower right,
Abell 370 is seen toward the constellation Cetus, the Sea Monster.
It is the last of six
galaxy clusters imaged
in the recently concluded
Frontier Fieldsproject.